This invention relates to a continuous polymerization process and products therefrom. In particular, this invention relates to a high temperature, high pressure, continuous polymerization process to produce oligomers. More particularly, this invention relates to a high temperature, high pressure, continuous polymerization process to produce terminally unsaturated and fully saturated oligomers. xe2x80x9cOligomers,xe2x80x9d as used herein and in the appended claims, refers to polymers having a degree of polymerization (xe2x80x9cdPxe2x80x9d) of less than 50.
The art has long sought an inexpensive, efficient and environmentally sound way to produce low molecular weight polymers. However, production of these low molecular weight polymers has proven to be difficult.
One method of achieving low molecular weight polymers is through the use of efficient chain transfer agents, but this approach has several drawbacks. First, this approach incorporates the structure of the chain transfer agent into the polymer chain. This can be undesirable since that structure will have an increasing effect on the properties of the polymer as molecular weight decreases. Furthermore, the chain transfer agents commonly employed are mercaptans. These materials are expensive and have objectionable odors associated with their presence. Other common chain transfer agents are hypophosphites, bisulfites and alcohols. These also add to the cost of the process, impart functionality to the polymer, may introduce salts into the product, and may necessitate a product separation step.
Another way of lowering the molecular weight of the polymers is by increasing the amount of initiator. This approach adds considerably to the cost of production and may result in polymer chain degradation, crosslinking, and high levels of unreacted initiator remaining in the product. In addition, high levels of initiator may also result in high levels of salt by-products in the polymer mixture which are known to be detrimental to performance in many applications. The same is true for chain stopping agents, such as sodium metabisulfite. Among the preferred free-radical initiators for aqueous polymerization is hydrogen peroxide. It is relatively inexpensive, has low toxicity, and does not produce detrimental salt by-products. However, hydrogen peroxide does not generally decompose efficiently at conventional polymerization temperatures and large amounts must normally be used to generate enough radicals to carry out a polymerization.
High levels of metal ions, alone or together with high levels of initiator, have also been tried as a means for controlling molecular weight. Such an approach is unsuitable for some products that cannot tolerate metal ion contaminants in the polymer product, such as pharmaceutical, medical and electronic applications. In addition, depending on the metal ions used, the product may be discolored due to the presence of the metal ions.
U.S. Pat. Nos. 4,680,352 and 4,694,054 disclose processes for preparing low molecular weight terminally-unsaturated oligomers employing metal chelate chain transfer agents to control molecular weight. These processes suffer from the same problems as those processes employing high level of metal ions, as described above. In addition, because the methods employing the metal chelate chain transfer agents undergo xcex2-scission reactions, they are limited to producing oligomers having homomethacrylate backbones.
In the European Polymer Journal, Volume 8, pages 321-328 (1972), Feit describes a multistep synthesis technique for preparing terminally-unsaturated oligomers and co-oligomers of vinyl monomers having electronegative groups. The process described therein requires a base-catalyzed addition of an acetic acid ester derivative to an activated olefin, followed by hydrolysis of one ester group, followed by a Mannich reaction to introduce a terminal double bond. This three step process is repeated to prepare a terminally-unsaturated oligomer with one additional mer. This process suffers the drawback of being fairly complex, expensive and time-consuming.
U.S. Pat. No. 5,710,227 discloses a high temperature, continuous polymerization process for preparing terminally unsaturated oligomers which are formed from acrylic acid and its salts, and acrylic acid and its salts with other ethylenically unsaturated monomers. The high temperature, continuous polymerization process solves many of the problems associated with previously known methods for preparing terminally-unsaturated oligomers formed from acrylic acid. However, the neat form of many of the acrylic acid products are solid and, thus, require the addition of a solvent to handle and use the products.
U.S. Pat. No. 4,356,288 discloses the preparation of terminally-unsaturated oligomers formed from esters of acrylic acid having a degree of polymerization of about 6-30 by an anionic polymerization reaction carried out in the presence of a catalytic amount of an alkoxide anion. The method is relatively complex. Because the method is inhibited by the presence of moisture (lowering yield and uniformity of the final product), it is not a viable commercial process.
In Chemical Engineering at Supercritical Fluid Conditions, pages 515-533 (1983), Metzger et al. disclose the dimerization and trimerization of methyl acrylate in benzene at a pressure of 200 bars and temperatures of 340-420xc2x0 C. in a flow reactor with a residence time of 5 minutes.
The present invention seeks to overcome the problems associated with the previously known methods for preparing oligomers by providing a polymerization process that is not limited to forming oligomers having only a homomethacrylate backbone or a carboxylic acid-containing monomer residue backbone and that does not require water or other solvent in the manufacture or use of the oligomer. The present invention also provides an oligomer free of metal, salt and surfactant contaminants, that, due to its purity and composition, is not water sensitive or discolored and is liquid when provided neat.
The invention is directed to a continuous process for preparing terminally-unsaturated and fully saturated oligomers which do not contain, as polymerized units, carboxylic acid-containing monomers, including the steps of:
(1) forming a reaction mixture, substantially free of carboxylic-acid monomers and their salts, containing:
(i) 0.5 to 99.95% by weight of the reaction mixture of at least one ethylenically unsaturated monomer; and
(ii) 0.05 to 25% by weight, based on the weight of the monomer, of at least one free-radical initiator; and
(2) continuously passing the reaction mixture through a heated zone wherein the reaction mixture is maintained at a temperature of at least 150xc2x0 C. and a pressure of at least 30 bars for from 0.1 seconds to 4 minutes to form terminally-unsaturated oligomers.
In addition, the invention is directed to a process for preparing fully saturated oligomers including the further step of hydrogenating the terminally unsaturated oligomer. The invention is also directed to processes for forming oligomers of vinyl acetate and oligomers of vinyl alcohol.
The process of the invention is useful for preparing oligomers of the formula: 
where
A, A1 and A2=
independently selected from xe2x80x94H;
C1-C50 straight-chain or branched alkyl, optionally substituted with a Y group;
C2-C50 straight-chain or branched alkenyl containing 1-5 double bonds, optionally substituted with 1-2 Y groups;
C5-C8 cycloalkyl, C5-C8 cycloalkenyl;
phenyl, (CH2)m-phenyl, 1- or 2-naphthyl;
xe2x80x94(Cxe2x95x90O)H; xe2x80x94C(OR1)2H;
xe2x80x94(Cxe2x95x90O)R1, xe2x80x94(Cxe2x95x90O)CF3; xe2x80x94C(OR1)2R1;
xe2x80x94(Cxe2x95x90O)OR, xe2x80x94O(Cxe2x95x90O)R1; xe2x80x94(Cxe2x95x90O)Cl;
xe2x80x94O(Cxe2x95x90O)OR1; xe2x80x94OR;
xe2x80x94(Cxe2x95x90O)NH2, xe2x80x94(Cxe2x95x90O)NHR1, xe2x80x94(Cxe2x95x90O)N(R1)2, xe2x80x94NH(Cxe2x95x90O)R1, xe2x80x94NH(Cxe2x95x90O)H, xe2x80x94(Cxe2x95x90O)NH(CH2)m(NH3)(+)(X)(xe2x88x92), xe2x80x94(Cxe2x95x90O)NH(CH2)m(NR1)2;
xe2x80x94Si(OR1)3, xe2x80x94Si(OR1)2R1, xe2x80x94Si(OR1)(R1)2, xe2x80x94Si(R1)3;
xe2x80x94F, xe2x80x94Cl, xe2x80x94Br, xe2x80x94I;
xe2x80x94Cxe2x89xa1N; oxiranyl;
xe2x80x94NH(Cxe2x95x90O)NH2, xe2x80x94NH(Cxe2x95x90O)NHR1,
xe2x80x94NH(Cxe2x95x90O)N(R1)2; 
xe2x80x94CH2CnF2n+1, xe2x80x94CH2CH2CnF2n+1, xe2x80x94CH(CF3)2, xe2x80x94CH2CnF2nH, xe2x80x94CH2CH2CnF2nH;
xe2x80x94P(xe2x95x90O)(OR1)3; xe2x80x94S(xe2x95x90O)2(OR1); xe2x80x94S(xe2x95x90O)2R1;
A3, A4=independently selected from xe2x80x94H, xe2x80x94F, xe2x80x94Cl, xe2x80x94Br, R1xe2x88x92;
E1, E2=independently selected from xe2x80x94H, 
G1, G2=independently selected from xe2x80x94H, xe2x80x94CH3, xe2x80x94(CH2)mCO2R1, xe2x80x94F, xe2x80x94Cl, xe2x80x94Br, xe2x80x94I;
M1, M2=independently selected from xe2x80x94H, xe2x80x94Cxe2x89xa1N, xe2x80x94(Cxe2x95x90O)OR1, xe2x80x94F, xe2x80x94Cl, xe2x80x94Br, xe2x80x94I;
Q=C1-C8 straight-chain or branched alkyl, xe2x80x94OR3, residue from radical decomposition of azo initiators (azonitrile, azoamidine, cyclic azoamidine, azoamide, azoalkyl classes) such as xe2x80x94C(R4)2Cxe2x89xa1N;
R=
C1-C50 straight-chain or branched alkyl, C2-C50 straight-chain or branched alkenyl containing 1-5 double bonds;
C5-C8 cycloalkyl, C5-C8 cycloalkenyl;
phenyl, (CH2)m-phenyl, 1- or 2-naphthyl, -4-benzoylphenyl (where any phenyl group may be substituted with up to 2 R2), anthracenyl, anthracenylmethyl;
xe2x80x94(CH2)mO(Cxe2x95x90O)R1, xe2x80x94(CH2)m(Cxe2x95x90O)OR1;
xe2x80x94(CH2)m(Cxe2x95x90O)R1;
xe2x80x94(CH2)m(Cxe2x95x90O)NH2, xe2x80x94(CH2)m(Cxe2x95x90O)NHR1,
xe2x80x94(CH2)m(Cxe2x95x90O)NH(R1)2;
xe2x80x94(CH2)mN(R1)2, xe2x80x94(CH2)mNH3(+)X(xe2x88x92);
xe2x80x94(CH2)mOR1, xe2x80x94(CH2CH2O)mR1, xe2x80x94(CH2CH(CH3)O)mR1, -2-tetrahydrofuranyl;
xe2x80x94(CH2)mNxe2x95x90Cxe2x95x90O;
xe2x80x94CH2CnF2n+1, xe2x80x94CH2CH2CnF2n+1, xe2x80x94CH(CF3)2, xe2x80x94CH2CnF2nH, xe2x80x94CH2CH2CnF2nH; 
xe2x80x83linear alkanes containing 1-5 epoxy groups derived from (poly)unsaturated vegetable oils;
xe2x80x94(CH2)pOH, xe2x80x94(CH2CH2O)mH, xe2x80x94[CH2CH(CH3)O]mH;
xe2x80x94(CH2)mSi(OR1)3, xe2x80x94(CH2)mSi(R1)(OR1)2, xe2x80x94(CH2)mSi(R1)2OR1, xe2x80x94(CH2)mSi(R1)3; 
R1=independently selected from C1-C8 straight chain or branched alkyl where (R1)2 may constitute a C5-C8 cycloalkyl group; phenyl, xe2x80x94CH2phenyl;
R2=C1-C6 straight chain or branched alkyl, C1-C6 straight chain or branched alkoxy, xe2x80x94CHO, xe2x80x94(Cxe2x95x90O)OR1, xe2x80x94N(R1)2, xe2x80x94NO2, xe2x80x94(Cxe2x95x90O)N(R1)2, xe2x80x94CF3, xe2x80x94(Cxe2x95x90O)R1; xe2x80x94F, xe2x80x94Cl xe2x80x94Br, xe2x80x94I;
R3=xe2x80x94H, C1-C8 straight chain or branched alkyl, xe2x80x94R1(Cxe2x95x90O), xe2x80x94R1(Cxe2x95x90O)O;
R4=C1-C18 straight-chain alkyl, C5-C8 cycloalkyl wherein the two adjacent R4 groups may together form a 5-8 membered ring, C1-C4 alkoxy-substituted straight-chain or branched C1-C8 alkyl groups;
X(xe2x88x92)=xe2x80x94F(xe2x88x92xe2x88x92), xe2x80x94Cl(xe2x88x92), xe2x80x94Br(xe2x88x92), xe2x80x94I(xe2x88x92), xe2x80x94HSO4(xe2x88x92), xe2x80x94H2PO3(xe2x88x92);
Y=xe2x80x94OH, xe2x80x94F, xe2x80x94Cl, xe2x80x94Br, xe2x80x94I, xe2x80x94NH2, xe2x80x94N(R1)2;
m=1-8
n=1-18
p=2-8
x=0-49
y=0-49
z=0-49
x+y+zxe2x89xa649.
The invention is also directed to a mixture that contains:
(1) about 50 to 90% by weight, based on the weight of the mixture, of a first oligomer having terminal unsaturation of Formula (1), where at least one of E1 and E2 is an endgroup of the formula: 
and when only one of E1 and E2 is an endgroup of Formula (II) then the other endgroup is selected independently from H, 
(2) about 10 to 50% by weight, based on the weight of the mixture, of a second oligomer having no terminal unsaturation of Formula (I), wherein E1 and E2 are independently selected from 
As used herein, the term xe2x80x9c(meth)acrylatexe2x80x9d refers to methacrylate and acrylate, the term xe2x80x9c(meth)acrylicxe2x80x9d refers to methacrylic and acrylic and the term xe2x80x9c(meth)acrylamidexe2x80x9d refers to methacrylamide and acrylamide. As used herein, the term xe2x80x9csubstantially freexe2x80x9d means less than 0.5% by weight. As used herein, the term xe2x80x9cambient conditionsxe2x80x9d means at a temperature of 20xc2x0 C.-40xc2x0 C. and at a pressure of 1 bar. As used herein, the term xe2x80x9chomooligomerxe2x80x9d means an oligomer containing the same monomer units and the term xe2x80x9cco-oligomerxe2x80x9d means an oligomer containing at least two different monomer units. As used herein, the term xe2x80x9cneatxe2x80x9d means a composition that contains only the oligomer and is substantially free of solvent and other additives. As used herein, the phrase xe2x80x9ccarboxylic-acid containing monomers and their saltsxe2x80x9d means monoethylenically unsaturated monocarboxylic acids, and the alkali metal, alkaline earth metal, and ammonium salts thereof, and monoethylenically unsaturated dicarboxylic acids, and the alkali metal, alkaline earth metal, and ammonium salts thereof, and the anhydrides of the cis-dicarboxylic acids.
The first step of the process of the invention is forming a reaction mixture, substantially free of carboxylic acid-containing monomers and their salts, containing:
(a) from 0.5 to 99.95% by weight of the reaction mixture of at least one ethylenically unsaturated monomer; and
(b) from 0.05 to 25% by weight, based on the weight of the ethylenically unsaturated monomer, of at least one free-radical initiator.
Preferably, the reaction mixture contains 10% to 99.9% by weight, and most preferably, 50% to 98% by weight, based on the weight of the reaction mixture, of at least one ethylenically unsaturated monomer. Preferably, the reaction mixture contains 0.1% to 5% by weight, and most preferably, 1% to 2% by weight, based on the weight of the ethylenically unsaturated monomer, of at least one free-radical initiator.
The process of the invention is suitable for polymerizing any ethylenically unsaturated monomer, except carboxylic acid-containing monomers and their salts. Suitable monomers include, but are not limited to,
n-alkyl(meth)acrylates, such as methyl acrylate, butyl methacrylate, octadecyl acrylate;
branched alkyl(meth)acrylates, such as isopropyl methacrylate, 2-ethyl hexyl acrylate, isobornyl methacrylate;
cycloalkyl(meth)acrylates, such as cyclopentyl methyl acrylate, cyclohexyl methacrylate;
straight chain or branched haloalkyl(meth)acrylates, such as 2,2,2-trifluoroethyl acrylate, hexafluoroisopropyl methacrylate, 2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-pentadecafluorooctyl acrylate;
aromatic alkyl(meth)acrylates, such as benzyl acrylate, 4-chlorophenethyl methacrylate;
aromatic (meth)acrylates, such as phenyl acrylate, 4-benzoyl phenyl acrylate;
hydroxyalkyl(meth)acrylates, such as 2-hydroxyethyl acrylate, 4-hydroxybutyl methacrylate;
heterocyclyl(meth)acrylates, such as 3-oxazolidinyl ethyl methacrylate, N-ethyl-ethylene ureido methacrylate;
aminoalkyl(meth)acrylates, such as N,N-dimethyl aminoethyl acrylate and acid salts of 2-aminoethyl acrylate, N,N-diethyl aminopropyl methacrylate;
ether-containing (meth)acrylates, such as ethoxyethoxyethyl acrylate, 2-tetrahydrofuranyl acrylate, ethyl ether of a polyalkoxylated ester of methacrylic acid;
silicon-containing (meth)acrylates, such as trimethoxysilylpropyl acrylate, diethoxymethylsilylpropyl methacrylate, isopropoxydimethylsilylpropyl acrylate;
(meth)acrylamides, such as N-methyl acrylamide, N,N-dimethylaminopropyl methacrylamide;
epoxide-containing (meth)acrylates, such as glycidyl (meth)acrylate, (meth)acrylates derived from partially or completely epoxidized (poly)unsaturated vegetable oils;
unsaturated alkyl(meth)acrylates, such as vinyl acrylate, allyl methacrylate, 2,4 hexadienyl methacrylate;
(meth)acrylate esters derived from (poly)unsaturated vegetable oils; terminal alkenes, such as ethylene, 1-hexene, 3-vinyl cyclohexene;
aralkenes, such as styrene, 4-methyl styrene, xcex1-methyl styrene, 4-methoxy styrene, 4-benzoyl styrene, 4-N,N-dimethylaminostyrene;
heterocyclyl alkenes, such as 2,-3, or 4-vinyl pyridines and N-vinyl imidazole;
dienes, such as butadiene, isoprene, vinylidene chloride, vinyl fluoride;
vinyl halides, such as vinyl chloride, tetrafluoroethylene;
vinyl esters, such as vinyl acetate, vinyl benzoate;
vinyl ketones, such as methyl vinyl ketone;
aldehyde containing vinyl functionality, such as (meth)acrolein and their acetal derivatives;
epoxyalkenes, such as 3,4-epoxybut-1-ene;
vinyl monomers, such as (meth)acrylonitrile, N-vinyl formamide, N-vinyl acetamide, fumaronitrile;
vinylsilanes and alkoxyvinylsilanes, such as vinyltrimethylsilane, vinyltrimethoxy silane, vinyldiethoxymethylsilane;
unsaturated diesters, such as dimethylmaleate, dibutylfumarate, diethyl itaconate;
functional (meth)acrylates, such as isocyanatoethyl methacrylate, acryloylchloride, aceto acetoxylethyl methacrylate
Preferred ethylenically unsaturated monomers include those monomers whose neat homooligomer of a degree of polymerization of about 5 to about 10 is a liquid under ambient conditions.
Suitable initiators for carrying out the processes of the present invention are any conventional free-radical initiators including, but are not limited to, hydrogen peroxide, certain alkyl hydroperoxides, dialkyl peroxides, peresters, percarbonates, persulfates, peracids, oxygen, ketone peroxides, azo initiators and combinations thereof Specific examples of some suitable initiators include hydrogen peroxide, oxygen, t-butyl hydroperoxide, di-tertiary butyl peroxide, tertiary-amyl hydroperoxide, methylethyl ketone peroxide and combinations thereof.
The monomers may be polymerized as dilute solutions, although the process does not require solvent, nor is the use of solvents preferred. The reaction mixture may contain one or more solvents at a level of from 0% to 99.5% by weight of the reaction mixture, preferably from 30% to 97% by weight of the reaction mixture, and most preferably from 50% to 95% by weight of the reaction mixture. As the relative amount of one or more solvents in the reaction mixture decreases, particularly below 60%, the molecular weight and the polydispersity of the resulting oligomer mixture increases. Suitable solvents for the process of the present invention are capable of dissolving the one or more monomers, especially under the supercritical fluid conditions of the process, and the oligomers formed therefrom. Suitable solvents for the present invention include, for example, ethers such as tetrahydrofuran, ketones such as acetone; esters such as ethyl acetate; alcohols such as methyl alcohol and butyl alcohol; alkanes such as hexane and heptane; aromatic hydrocarbons such as benzene, toluene and xylene; supercritical fluids such as carbon dioxide; water; and mixtures thereof. Supercritical fluids such as carbon dioxide are particularly useful because the solvent readily is stripped from the product and may be recycled.
In the second step of the process of the present invention, the reaction mixture is continuously passed through a heated zone, wherein the reaction mixture is maintained at a temperature of at least 150xc2x0 C. under elevated pressure. Once the reaction mixture is formed, it is preferable to have the passing reaction mixture reach the polymerization temperature as rapidly as possible. Preferably, the reaction mixture reaches the polymerization temperature within 2 minutes, more preferably within 1 minute, most preferably within 30 seconds. Prior to reaching the reaction temperature, the reaction mixture may be at any suitable temperature, preferably at a temperature of from room temperature to 450xc2x0 C., most preferably from a temperature of from room temperature to 60xc2x0 C. to 400xc2x0 C. The oligomerization is conducted at a temperature of at least 150xc2x0 C., and is preferably conducted at a temperature in the range of from 200xc2x0 C. to 500xc2x0 C., and most preferably at a temperature in the range of from 275xc2x0 C. to 450xc2x0 C. At temperatures below 150xc2x0 C., the molecular weight of the oligomer increases and the relative amount of by-products, particularly non-terminally unsaturated compounds, increases.
The oligomerization at the elevated temperatures of the process of the invention is rapid. Thus, the reaction mixture can be maintained at the polymerization temperature for as little as 0.1 seconds up to 4 minutes, preferably from 0.5 seconds to 2 minutes, most preferably from 1 second to 1 minute. Under extended periods of time at which the reaction mixture is exposed to the polymerization temperature, the yield of terminally unsaturated oligomer decreases. However, extended periods at the polymerization temperature have been found to have little effect on both the conversion of monomer and the molecular weight of the products formed.
The elevated temperatures of the polymerization require that the polymerization reactor be equipped to operate at elevated pressure of at least 30 bars to maintain the contents of the reactor as a fluid at the reaction temperature. In general, it is preferred to conduct the polymerization at from 70 bars to 350 bars, and more preferably at from 200 bars to 300 bars.
In the process of the present invention, the ethylenically unsaturated monomers, initiator and, optionally, solvent are combined to form a reaction mixture. The order of combining the components of the reaction mixture is not critical to the process of the present invention. In one embodiment of the present invention, it may be desirable to use one or more solvents, heat the one or more solvents to an elevated temperature, and add the one or more monomers and the at least one initiator to the heated solvent to form the reaction mixture. It is preferred to add the initiator last. The reaction mixture can be formed at a temperature below, at or above the oligomerization temperature. In one embodiment of the invention, it may be desirable to add an additional amount of solvent to the oligomer product while the oligomer product is at an elevated temperature to maintain desirable fluidity and viscosity properties of the oligomer product.
Reactors suitable for use in the process of invention include tubular reactors having no moving parts and of any cross-sectional shape that permit continuous, steady state flow and that may operate under elevated temperatures and pressures. Such reactors are typically made from inert materials, such as stainless steel or titanium. The reactor may be of any length and cross-sectional dimension that permits effective temperature and pressure control.
Depending upon the final application of the oligomeric products of the invention, the reaction mixture may optionally contain metal ions, such as copper, nickel or iron ions or combinations thereof. However, their presence is not preferred.
The process of the present invention generally results in a relative conversion of the monomers into oligomer product of from 10% to greater than 95% relative to the initial amount of the one or more monomers present in the reaction mixture. If residual monomer levels in the oligomer mixture are unacceptably high for a particular application, their levels can be reduced by any of several techniques known to those skilled in the art, including rotary evaporation, distillation, and vacuum distillation. Preferably, any residual monomers which may be present in the oligomer mixture are distilled or xe2x80x9cstrippedxe2x80x9d and recycled for later use.
The process of the present invention results in oligomers having low molecular weights and narrow polydispersities. Furthermore, embodiments of the process result in products that do not require the removal of organic solvents (if none were used in the process) and are not contaminated with high levels of salt. The process of the present invention may be used to produce oligomers having number average molecular weights below 5,000, preferably below 3,000, and most preferably from 200 to 1,000.
The process of the invention may contain an optional third step wherein the terminal unsaturation of the terminally unsaturated oligomers is removed by hydrogenation under conditions known to those skilled in the art, with or without solvent. Preferably, the hydrogenation may be carried out utilizing a wide variety of hydrogenation catalysts on an alkaline metal salt support. Preferred metal catalysts include those comprising metals selected from groups 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12 of the Periodic Table of Elements as published in Chemical and Engineering News 63(5), 27, 1985, is preferably present in the reaction at a ratio of 0.01 to 5.0, and preferably 0.02 to 2.0 grams of catalyst per gram of unsaturated oligomer. The degree of hydrogenation is determined from proton NMR measurements at 25xc2x0 C. using oligomer solutions in CDCl3 with TMS as the internal reference. Upon hydrogenation the resonances associated with olefinic protons are converted to aliphatic protons. Thus the saturation efficiency can be measured by analyzing the remaining olefinic proton resonances.
The process of the invention is useful for preparing oligomers of the formula: 
where
A, A1 and A2=
independently selected from xe2x80x94H;
C1-C50 straight-chain or branched alkyl, optionally substituted with a Y group;
C2-C50 straight-chain or branched alkenyl containing 1-5 double bonds, optionally substituted with 1-2 Y groups;
C5-C8 cycloalkyl, C5-C8 cycloalkenyl;
phenyl, (CH2)m-phenyl, 1- or 2-naphthyl;
xe2x80x94(Cxe2x95x90O)H; xe2x80x94C(OR1)2H;
xe2x80x94(Cxe2x95x90O)R1, xe2x80x94(Cxe2x95x90O)CF3; xe2x80x94C(OR1)2R1;
xe2x80x94(Cxe2x95x90O)OR, xe2x80x94O(Cxe2x95x90O)R1; xe2x80x94(Cxe2x95x90O)Cl;
xe2x80x94O(Cxe2x95x90O)OR1; xe2x80x94OR;
xe2x80x94(Cxe2x95x90O)NH2, xe2x80x94(Cxe2x95x90O)NHR1, xe2x80x94(Cxe2x95x90O)N(R1)2, xe2x80x94NH(Cxe2x95x90O)R1, xe2x80x94NH(Cxe2x95x90O)H, xe2x80x94(Cxe2x95x90O)NH(CH2)m(NH3)(+)(X)(xe2x88x92), xe2x80x94(Cxe2x95x90O)NH(CH2)m(NR1)2;
xe2x80x94Si(OR1)3, xe2x80x94Si(OR1)2R1, xe2x80x94Si(OR1)(R1)2, xe2x80x94Si(R1)3;
xe2x80x94F, xe2x80x94Cl, xe2x80x94Br, xe2x80x94I;
xe2x80x94Cxe2x89xa1N; oxiranyl;
xe2x80x94NH(Cxe2x95x90O)NH2, xe2x80x94NH(Cxe2x95x90O)NHR1, xe2x80x94NH(Cxe2x95x90O)N(R1)2; 
xe2x80x94CH2CnF2n+1, xe2x80x94CH2CH2CnF2n+1, xe2x80x94CH(CF3)2, xe2x80x94CH2CnF2nH, xe2x80x94CH2CH2CnF2nH;
xe2x80x94P(xe2x95x90O)(OR1)3; xe2x80x94S(xe2x95x90O)2(OR1); xe2x80x94S(xe2x95x90O)2R1;
A3, A4=independently selected from xe2x80x94H, xe2x80x94F, xe2x80x94Cl, xe2x80x94Br, R1;
E1, E2=independently selected from xe2x80x94H, 
G1, G2=independently selected from xe2x80x94H, -CH3, xe2x80x94(CH2)mCO2R1, xe2x80x94F, xe2x80x94Cl, xe2x80x94Br, xe2x80x94I;
M1, M2=independently selected from xe2x80x94H, xe2x80x94Cxe2x89xa1N, xe2x80x94(Cxe2x95x90O)OR1, xe2x80x94F, xe2x80x94Cl, xe2x80x94Br, xe2x80x94I;
Q=C1-C8 straight-chain or branched alkyl, xe2x80x94OR3, residue from radical decomposition of azo initiators (azonitrile, azoamidine, cyclic azoamidine, azoamide, azoalkyl classes) such as xe2x80x94C(R4)2Cxe2x89xa1N;
R=
C1-C50 straight-chain or branched alkyl,
C2-C50 straight-chain or branched alkenyl containing 1-5 double bonds;
C5-C8 cycloalkyl, C5-C8 cycloalkenyl;
phenyl, (CH2)m-phenyl, 1- or 2-naphthyl, -4-benzoylphenyl (where any phenyl group may be substituted with up to 2 R2), anthracenyl, anthracenylmethyl;
xe2x80x94(CH2)mO(Cxe2x95x90O)R1, xe2x80x94(CH2)m(Cxe2x95x90O)OR1;
xe2x80x94(CH2)m(Cxe2x95x90O)R1;
xe2x80x94(CH2)m(Cxe2x95x90O)NH2, xe2x80x94(CH2)m(Cxe2x95x90O)NHR1, xe2x80x94(CH2)m(Cxe2x95x90O)NH(R1)2;
(CH2)mN(R1)2, xe2x80x94(CH2)mNH3(+)X(xe2x88x92);
xe2x80x94(CH2)mOR1, xe2x80x94(CH2CH2O)mR1, xe2x80x94(CH2CH(CH3)O)mR1, -2-tetrahydrofuranyl;
xe2x80x94(CH2)mNxe2x95x90Cxe2x95x90O;
xe2x80x94CH2CnF2n+1, xe2x80x94CH2CH2CnF2n+1, xe2x80x94CH(CF3)2, xe2x80x94CH2CnF2nH, xe2x80x94CH2CH2CnF2nH; 
xe2x80x83linear alkanes containing 1-5 epoxy groups derived from (poly)unsaturated vegetable oils;
xe2x80x94(CH2)pOH, xe2x80x94(CH2CH2O)mH, xe2x80x94[CH2CH(CH3)O]mH;
xe2x80x94(CH2)mSi(OR1)3, xe2x80x94(CH2)mSi(R1)(OR1)2, xe2x80x94(CH2)mSi(R1)2OR1, xe2x80x94(CH2)mSi(R1)3; 
xe2x80x94(CH2)mO(Cxe2x95x90O)CH2(Cxe2x95x90O)R1;
R=independently selected from C1-C8 straight chain or branched alkyl where (R1)2 may constitute a C5-C8 cycloalkyl group; phenyl, xe2x80x94CH2phenyl;
R2=C1-C6 straight chain or branched alkyl, C1-C6 straight chain or branched alkoxy, xe2x80x94CHO, xe2x80x94(Cxe2x95x90O)OR1, xe2x80x94N(R1)2, xe2x80x94NO2, xe2x80x94(Cxe2x95x90O)N(R1)2, xe2x80x94CF3, xe2x80x94(Cxe2x95x90O)R1; xe2x80x94F, xe2x80x94Cl, xe2x80x94Br, xe2x80x94I;
R3=xe2x80x94H, C1-C8 straight chain or branched alkyl, xe2x80x94R1(Cxe2x95x90O), xe2x80x94R1(Cxe2x95x90O)O;
R4=C1-C18 straight-chain alkyl, C5-C8 cycloalkyl wherein the two adjacent R4 groups may together form a 5-8 membered ring, C1-C4 alkoxy-substituted straight-chain or branched C1-C8 alkyl groups;
X(xe2x88x92)=xe2x80x94F(xe2x88x92xe2x88x92), xe2x80x94Cl(xe2x88x92), xe2x80x94Br(xe2x88x92), xe2x80x94I(xe2x88x92), xe2x80x94HSO4(xe2x88x92), xe2x80x94H2PO3(xe2x88x92);
Y=xe2x80x94OH, xe2x80x94F, xe2x80x94Cl, xe2x80x94Br, xe2x80x94I, xe2x80x94NH2, xe2x80x94N(R1)2;
m=1-8
n=1-18
p=2-8
x=0-49
y=0-49
z=0-49
x+y+zxe2x89xa649.
It is understood that the residues of the monomers, Z1, Z2 and Z3, in the oligomers of Formula (I) above may be randomly arranged to form alternating, random or block polymer structures. It is also understood that, not only are homooligomers and co-oligomers contemplated, but oligomers formed from more than two different types of monomers, such as low molecular weight terpolymers or xe2x80x9cter-oligomersxe2x80x9d, are also contemplated. In the broadest sense, it is understood that in the oligomer where there are up to 49 possible residues of monomers (whether of Z1, Z2 or Z3 structure) the monomers are each independently selected such that it would be possible to form an oligomer from 49 different monomers.
The process of the present invention is useful for producing a mixture of oligomers containing:
(1) about 50 to 90% by weight, based on the weight of the mixture, of a first oligomer having terminal unsaturation of Formula (I), where at least one of E1 and E2 is an endgroup of the formula: 
and when only one of E1 and E2 is an endgroup of Formula (II) then the other endgroup is selected independently from H, 
(2) about 10 to 50% by weight, based on the weight of the mixture, of a second oligomer having no terminal unsaturation of Formula (I), wherein E1 and E2 are independently selected from 
The mixture may optionally contain an oligomer formed by a chain-chain termination reaction.
Terminal unsaturation may be detected and measured by conventional techniques, including 1H NMR spectroscopy, 13C NMR spectroscopy, and bromine titration. The endgroups may be identified by conventional techniques, including MALDI-MS.
The terminally-unsaturated oligomers, fully saturated oligomers and mixtures of the invention may be supplied neat and flow under ambient conditions. The consistency of the products ranges from a thin, water-like fluid to a viscous, taffy-like fluid. Furthermore, they do not require the use of water or other solvents in the preparation or use and are substantially free of contaminants, including, salts, surfactants, metals and the like.
The oligomers of the invention may be used neat, provided in solvent or provided emulsified in water with at least one surfactant. The emulsified oligomer in water is preferred if the neat form of the oligomer is too viscous for use in an application. Suitable surfactants include conventional anionic, cationic, nonionic, amphoteric surfactants and mixtures thereof. The surfactant may be added at a level of at least 0.1% solids based on the weight of the oligomer. The emulsified composition may be prepared by mixing at least one surfactant, at least one oligomer, water and mixing vigorously. Other minor components, such as wetting agent, may be added to the emulsified composition. Alternatively, the emulsified composition may be prepared by adding the surfactant to the reaction mixture containing the ethylenically unsaturated monomer and initiator prior to oligomerization.
The oligomers of the invention are useful in many applications, including, for example, in binders and additives (surfactants, emulsifiers, rheology modifiers) for architectural coatings (paints, primers, lacquers, varnishes, stains, EIFS); in industrial coatings (including automotive finishes, metal finishes, printing inks and resins); in building products (wood coatings and binders, caulks, sealants, concrete modifiers and coatings, impregnants, polishes) in coatings and additives for paper, textiles, and nonwovens; in adhesives; in leather chemicals; in formulation chemicals (including detergents, dispersants, water treatment, scale inhibitors, suspension aids); in plastics and plastic additives (plasticizers, processing aids); in rubber and rubber additives (plasticizers, processing aids); in biocides and adjuvants; in agricultural chemicals and adjuvants; in electronic chemicals; in ion exchange resins (adsorbents and adsorbents); in oil additives; in solvents; in lubricants and hydraulic fluids; and the like.